Azo compounds and their production



Patented Nov. 2, 1937 UNlTED TET oFricE,

2,097,638 AZO ooMPouNns AND THEIR PRODUCTION James P. Penny, B ufialo, N. Y., assignor to National Aniline & Chemical Company, Inc., New York, N. Y., a corporation of New York No Drawing. Application March 13, 1933,

Serial No. 660,465 a diazo compound of an arylamine of the benezene or naphthalene series, or the diazo compound of an aminoazo body of the benzene series, said diazo compounds also being free from an acid salt-forming group; I have discovered that these dyestuffs are soluble in organic solvents, more particularly organic liquids which contain oxygen in their composition, and especially those which are aliphatic compounds; Thus composi- -tions containing an alcohol, ester, ether, ketone and the like may be colored by these dyestufls. For example, solutions of one or more of these dyestuffs in one or more organic solvents may be used to color resinous compositions, both of the 25 natural and synthetic types, and cellulose derivatives (esters, ethers, nitrates, etc.); as for example, cresol resins, pyroxylin and other lacquers, shellac, Celluloid, cello-glass, leather finishes, compositions for air brush work, etc. I lo have found, furthermore that these dyes in solution in organic solvents, especially alcohols, are particularly suitable for use as wood stains, since, when used alone or in combination, they permit the production of a variety of stains which pos- |5 sess good fastness to light.

According to the present invention new dyestufi's which are of particular value for such uses can be obtained by coupling N-aryl or N- aralkyl-I-acids, particularly the former, with di- 9 azotized xylidines or aminoazo-xylenes, and especially those which are derived from o-xylidines or mixtures of xylidines containing a major proportion of o-xylidines. I have found that the dyestuffs derived from such o-Xylidines are soluble to a greater extent in organic solvents than are the dyestuffs derived from technical xylidine, which ordinarily contains a relatively small proportion of o-xylidines,

D 1 For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description and illustrative examples of the preparation and use of dyestufis to which this invention relates. It will i be understood, however, that the invention is not '10 Claims. 7 (Cl. 260--92) limited thereto except as limited by the appended patent claims.- The parts are by weight.

Example 1.'Thirty-three (33) parts of N-' phenyl-I-acid (2-phenylamino-5-naphthol-7-sulfonic acid) are dissolved in 400 parts of water containing 40 parts of sodium carbonate. To this solution, which is cooled to 0 C. by addition thereto of excess ice (about 200 parts), there is slowly added, with stirring, the solution obtained by diazotizing 12.1 parts of return ortho-Xylil0 dine in 200 parts of Water by means of 28 parts of Be. hydrochloric acid and 7.2 parts of sodium nitrite of 96 per cent. purity. The temperature of the reaction mixture is maintained at about 0 C. during the mixing of the reagents 15.:

and their reaction. When the reaction is complete the mixture is heated to about 85 C., then cooled to about 80 C. and the solid azo dye thus formed is filtered off from the liquid. By a coupling reaction between the phenyl-I-acid and the diazotized ortho-xylidine, the compound 0- xylyl-azo-phenyl-I-acid is formed. The azo dye thus obtained is, in the dry state, a reddish powder which is soluble in ethanol, acetone, amyl acetate, methanol, ethylene glycol, diethylene glycol, the monobutyl ethers of ethylene glycol and of diethylene glycol, and other oxygen-containing organic solvents. It is practically insolu- I ble in hydrocarbons of the benzene series.

A 4 per cent. solution of the dyestuiT in alcohol v 30 stains wood a red color of good fastness to light. The wood thus stained may be subsequently coated with shellac and then varnished, waxed or coated with a suitable lacquer. The dyestufi is particularly suited for use in wood stains containing diethylene glycol, triethanolamine or a similar product preventing raising of the grain. The dyestufi solutions may be applied by brushing, dipping or spraying the Wood.

The dyestuff is also of value for staining leather 40 F and for coloring lacquers, resins (particularly synthetic resins in the resol stage), and in general it may be used in the same manner and for the same purposes as other alcohol-soluble dyes heretofore known to the art. stantial insolubility in benzene, celluloid compositions colored with it can be cemented to White or other colored celluloid or related compositions without bleeding.

The. return ortho-xylidine employed in the above example is a residual product obtained by treating a commercial or technical xylidine" which contans a large proportion of metaand/or para-xylidines and a small proportion of ortho-xylidines with glacial acetic acid to precip- In view of itssub- 45 Gamma-acid itate meta-xylidine as the acetate; filtering off the precipitate; then treating the resulting filtrate with hydrochloric acid to precipitate paraxylidine as the hydrochloride; and filtering off the resulting precipitate from the remaining solution of ortho-Xylidine hydrochlorides (as described for example in Journal of the Chemical Society (London), vol. 77, p. 65 (1900)).

Example 2.-If in the process of Example 1 a xylidine is used which has been prepared by the nitration and reduction in the usual manner of a high-boiling xylene fraction of tar distillate (for example, an ortho-xylene distillate having a boiling point of 141 C. to 144 0.), a product is obtained Which is soluble in alcohol giving a red solution and which may be used in the place of the dyestuif in Example 1 in its various technical applications. The product is, however, somewhat less soluble in alcohol than the dyestuif of Example 1.

The chief products obtained by the processes of Examples 1 and 2 may be represented in the free state by the formula:

By replacing the N-phenyl-I-acid employed in the above examples by its equivalent of another N-aryl-I-acid or N-aralkyl-I-acid (as for example, N-benzyl-, N-tolyl-, N-xylyl-, N-anisidyl-, N-naphthyl-I-acid, etc.), other o-xylyl-azo-I- acid derivatives may be obtained. In the free state these compounds may be represented by the general formula:

in which R represents an aryl or aralkyl radical which is free from an acid salt-forming group, and especially from a carboxyl and a sulfonic acid group.

Furthermore, the N-phenyl-I-acid of the above examples may be replaced by other N-aryl-, or N-aralkyl-, monoamino-monohydroxy-naphthalene-monosulfonic acids; phenyl-, N-tolyl-, N-xylyl-, N-anisidyl, N-naphthyl-, N-benzyl, and the like derivatives of (2-amino-8-naphthol-6-sulfonic acid), of 1-amino-8naphthol-4-sulfonic acid, etc. All of the said products in the free state may be represented by the general formula:

in which R represents an aryl or aralkyl radical which is free from an acid salt-forming group, and especially from a carboxyl and a sulfonic acid group.

Other dyes soluble in organic solvents, and useful in the coloring of material in accordance with the present invention, may be prepared in a similar manner from N-aryl-I-acids or other N- aryl-, or N-aralkyl-, monoamino-monohydroxynaphthalene monosulfonic acids and other diaas for example, N-

formula:

6H By coupling diazotized cresidine with phenyl- I-acid in alkaline solution, a dyestuff is obtained which is soluble in alcohol to yield a red solution. This dyestuff in the free state may be represented by the formula:

HOsS OHaO The dyestuff obtained by coupling diazobenzene with phenyl-I-acid in alkaline solution is soluble in alcohol to give an orange solution. The formula of the dyestuff in the free state may be represented as:

The dyestuff obtained by coupling diazotized amino-azoxylene with phenyl-I-acid in alkaline solution is soluble in alcohol to yield a violet solution. The dyestuif in the free state may be represented by the formula:

(CH3): I

The new dyestuffs, produced as above described, in the free state may be represented by the formula:

NHR

SOaH

in which R and R' represent radicals which are free from acid salt-forming groups, R represents further an aryl or aralkyl radical, and R represents a radical comprising the xylyl group.

In general, dyestuffs suitable for the coloring of materials in accordance with the present invention correspond in the free state with the general formula:

NHR

in which R and R" represent radicals which are free from acid salt-forming groups, R represents further an aryl or aralkyl radical, and R represents further an aryl radical of the benzene or the naphthalene series. The aryl radicals represented by R" in theabove formula may con tain elements or groups as substituents, provided these substituents. are also free from an acid salt-forming group, and especially from carboxyl and sulfonic acid groups. Suitable substituents are, for example, alkyl, nitro, amino, alkylamino, arylamino, alkoxy, halogen, arylazo, and the like. These dyestufis may be prepared, for example, by coupling an N-aryl, or an;N-aralkyl, derivative of a moncamino-monohydroXy-naphthalenemonosulfonic acid, preferably in an alkaline medium, with a diazotized substituted or un-. substituted arylamine of the benzene or naphthalene series which is free from an acid saltforming group; as for example, diazotized m-,

p-xylidine, and their mixtures; diazotized cumidine; diazotized o-, m-, p-nitraniline; diazotized o-, m-, p-aminophenols and their ethers; diazotized nitro-aminophenols, nitro-aminocresols, and their ethers; diazotized alphaand betanaphthylamines; diazotized aminonaphthols and xylenes and their mixtures; etc.

I claim:

1. A composition of matter comprising an azo coloring matter corresponding in the free state with the formula their ethers; the various diazotized aminoazoin which R represents a radical of the group consisting of aryl and aralkyl radicals, and R' represents a radical comprising the xylyl-group, the radicals R and R' being free from an acid salt-forming group, which azo coloring matter is' obtainable by coupling a diazo xylene compound free from an acid salt-forming group, in an alkaline medium, with an amino naphthol sulfonic acid corresponding in the free state with the formula NHR CroHr-SOaH in which R represents a radical of the group consisting of aryl and aralkyl radicals, said radical being free from an acid salt-forming group.

2. A composition of matter comprising an azo coloring matter corresponding in the free state with the formula HOaS NHR in which R represents a radical of the group consisting of the aryl and aralkyl radicals, said radical being free from an acid salt-forming group, said coloring matter being soluble in alcohol.

3. A composition of matter comprising an oxylyl-azo compound corresponding in the free state with the formula NH R , in which R represents a radical of the group con-- sisting of aryl and aralkyl radicals, said radical being free from an acid salt-forming group, said compound being soluble in alcohol and beingobtainable by coupling diazotized ortho-xylidine' in an alkaline medium with an amino naphthol sul ionic acid corresponding in the free state with the formula CmH4-OH \NHR in which R represents a radical of the group consisting of aryl and aralkyl radicals, said radical being free from an acid salt-forming group.

4. A composition of matter comprising o-xylylazo-N-phenyl-I-acid corresponding in the free state with the formula (o-)(CHa)zCoHsN=N said compound being soluble in alcohol to give a' red solution.

5. A composition of matter comprising an azo coloring matter corresponding in the free state with the formula with the formula NHR S 0311 OH4 in which R represents a radical of the group consisting of aryl and aralkyl radicals, said radical being free from an acid salt-forming group, and. X represents a member of the group consisting of hydrogen and the radio-a1 said coloring matter being soluble in alcohol and obtainable by diazotizing the corresponding xylidine compound and coupling the diazotized product in an alkaline medium with an amino naphthol sulfonic acid corresponding in the free state with the formula xoHs-S OaH in which R represents a radical of the group con.

sisting of the aryl and'aralkyl radicals, said radical-being free from an acid salt-pforming group.

8. A composition of matter comprising an azo coloring matter corresponding in the free state 5; with the formula I OH in which X represents a member of the group consisting of hydrogen and the radical 25; Hols said coloring matter being soluble in alcohol and,

obtainable by diazotizing the corresponding 0- Xylidine and coupling in an alkaline medium with an amino naphthol sulfonic acid corresponding in the free state with the formula 11 (p-MD [V 10. A composition of matter comprising an azo coloring mattercorresponding in the free state with the formula and obtainable by diazotizing ortho-xylidine andcoupling the diazotized product in an alkaline medium with Z-phenylamino-5-naphthol-'7-sulfonic acid, the sodium salt of said coloring matter being soluble in ethyl alcohol, methyl alcohol,

and other oxygen-containing organic solvents, and substantially insoluble in benzene.

JAMES P. PENNY. 

